The IEP of magnesium aluminum hydroxide was predicted with the modified Yoon′s equation, and the effect of electrolyte on the Y- potential of the sol was studied by electrophoresis method. The results showed that ...The IEP of magnesium aluminum hydroxide was predicted with the modified Yoon′s equation, and the effect of electrolyte on the Y- potential of the sol was studied by electrophoresis method. The results showed that the calculated IEP values with the modified Yoon′s equation agreed well with the experimental ones. With the increase of the ionic radius of monovalent anions (Cl -, Br -, I -) the ζ potential decreased. The same was true for CO 2- 3, SO 2- 4 but the sign of the Y- potential reversed from positive to negative. For Al 3+ , Ca 2+ , Mg 2+ , however, the ζ potential increased with the increase of the concentration of Al 3+ , Ca 2+ , Mg 2+ .展开更多
Yoon's equation which predicted point of zero charge of complex oxide should predict the zero point of net charge (ZPNC) of mixture of variable and permanent charge rather than the point of zero charge (PZC) of th...Yoon's equation which predicted point of zero charge of complex oxide should predict the zero point of net charge (ZPNC) of mixture of variable and permanent charge rather than the point of zero charge (PZC) of the variable charge component. The calculated values with modified Yoon's equation agreed with the experimental values.展开更多
The coordination structure of aluminum in magnesium aluminum hydroxide was studied by 27Al NMR. The result showed that tetrahedral aluminum (AlIV) existed in magnesium aluminum hydroxide, and the contents of AlIV inc...The coordination structure of aluminum in magnesium aluminum hydroxide was studied by 27Al NMR. The result showed that tetrahedral aluminum (AlIV) existed in magnesium aluminum hydroxide, and the contents of AlIV increased with the increase of the ratio of Al/Mg and with the peptizing temperature. AlIV originated from the so-called Al13 polymer with the structure of one Al tetrahedron surrounded by twelve Al octahedrons.展开更多
The isoelectric point (IEP) and zero point of charge (ZPC) of magnesium aluminum hydroxide were studied by electrophoresis method, potentiometric titration method, and elemental analysis. Results showed that the charg...The isoelectric point (IEP) and zero point of charge (ZPC) of magnesium aluminum hydroxide were studied by electrophoresis method, potentiometric titration method, and elemental analysis. Results showed that the charge of magnesium aluminum hydroxide was composed of variable charge and permanent positive charge. Because of the permanent positive charge, the IEP and ZPC obtained were higher than calculated. The LEP decreased and ZPC increased as X increased.展开更多
The influence of pH on the thixotropy of pure kaolinite suspension and magnesium aluminum hydroxide (Mg-Al-MMH)-kaolinite suspension was studied. The results show that the thixotropic type of pure kaolinite suspension...The influence of pH on the thixotropy of pure kaolinite suspension and magnesium aluminum hydroxide (Mg-Al-MMH)-kaolinite suspension was studied. The results show that the thixotropic type of pure kaolinite suspension was not affected by pH studied in the range of 3.60– 12.00. The thixotropic type of Mg-Al-MMH-kaolinite suspension with mass ratio (R) value of MMH to kaolinite 0.029 transformed from complex thixotropy into positive thixotropy with increasing of pH in the range of pH 3.83–12.00, and the type of thixotropy of Mg-Al-MMH-kaolinite suspension withR = 0.129 transformed from positive thixotropy into complex thixotropy with increasing of pH in the range of pH 3.70–11.96.展开更多
文摘The IEP of magnesium aluminum hydroxide was predicted with the modified Yoon′s equation, and the effect of electrolyte on the Y- potential of the sol was studied by electrophoresis method. The results showed that the calculated IEP values with the modified Yoon′s equation agreed well with the experimental ones. With the increase of the ionic radius of monovalent anions (Cl -, Br -, I -) the ζ potential decreased. The same was true for CO 2- 3, SO 2- 4 but the sign of the Y- potential reversed from positive to negative. For Al 3+ , Ca 2+ , Mg 2+ , however, the ζ potential increased with the increase of the concentration of Al 3+ , Ca 2+ , Mg 2+ .
文摘Yoon's equation which predicted point of zero charge of complex oxide should predict the zero point of net charge (ZPNC) of mixture of variable and permanent charge rather than the point of zero charge (PZC) of the variable charge component. The calculated values with modified Yoon's equation agreed with the experimental values.
基金This research is supported by NNSFC No:20273041.
文摘The coordination structure of aluminum in magnesium aluminum hydroxide was studied by 27Al NMR. The result showed that tetrahedral aluminum (AlIV) existed in magnesium aluminum hydroxide, and the contents of AlIV increased with the increase of the ratio of Al/Mg and with the peptizing temperature. AlIV originated from the so-called Al13 polymer with the structure of one Al tetrahedron surrounded by twelve Al octahedrons.
文摘The isoelectric point (IEP) and zero point of charge (ZPC) of magnesium aluminum hydroxide were studied by electrophoresis method, potentiometric titration method, and elemental analysis. Results showed that the charge of magnesium aluminum hydroxide was composed of variable charge and permanent positive charge. Because of the permanent positive charge, the IEP and ZPC obtained were higher than calculated. The LEP decreased and ZPC increased as X increased.
基金the National Natural Science Foundation of China (Grant No. 29873026).
文摘The influence of pH on the thixotropy of pure kaolinite suspension and magnesium aluminum hydroxide (Mg-Al-MMH)-kaolinite suspension was studied. The results show that the thixotropic type of pure kaolinite suspension was not affected by pH studied in the range of 3.60– 12.00. The thixotropic type of Mg-Al-MMH-kaolinite suspension with mass ratio (R) value of MMH to kaolinite 0.029 transformed from complex thixotropy into positive thixotropy with increasing of pH in the range of pH 3.83–12.00, and the type of thixotropy of Mg-Al-MMH-kaolinite suspension withR = 0.129 transformed from positive thixotropy into complex thixotropy with increasing of pH in the range of pH 3.70–11.96.
